Colors have played a vital role in human life—be it beverages, foods, cosmetics, prescription drugs, etc. While plant sources for natural colors have been known for a long time, synthetic colors have predominated in the human environment all along largely because of cost effectiveness. In the past decade or so, there has been increasing interest in the use of natural colors instead of synthetic colors in beverages and the food chain in order to eliminate potential adverse effects associated with synthetic compounds. A major surge in natural colors seems to emerge from recent reports that anthocyanidins (anthos)/anthocyanins from berries are protective against various cancers, aid in reversal of memory loss, are anti-diabetic, and protective against cardiovascular disease. For example, recent studies have shown synergistic anti-tumor activity of a native mixture of anthos isolated from bilberry against human lung cancer xenograft in nude mice. Anti-cancer activity of anthos/anthocyanins is implicated against breast cancer, colon cancer and esophageal cancer based on various cell culture and/or in vivo studies. Native anthos isolated from bilberry, a European ‘cousin’ of blueberry, also showed dose-dependent kill of human pancreatic cancer cells in cell culture.
Anthocyanins are anthos conjugated to a variety of sugars (glucosides, arabinosides, etc.—as mono-, di- and tricyclic). While over 500 anthocyanins are reported, most of them are derivatives of six major anthos, namely, delphinidin (Dp), cyanidin (Cy), peonidin (Pe), petunidin (Pt), malvidin (Mv) and pelargonidin (Pg). These anthos are structural analogs, and are present in different berries (e.g., blueberry, black berry, black raspberry, strawberry, cranberry), and other dark-colored fruits (e.g., red and black grapes, plums), vegetables (e.g., purple cabbage, purple potatoes, purple sweet potatoes, purple corn) and grains (e.g., black beans, black lentils, black soy beans, black rice). However, the classical methods to isolate anthos are cumbersome and time consuming, requiring days and weeks for their isolation, and are not economical for commercial production.
Research efforts are being directed toward the isolation of anthos/anthocyanins in bulk quantities. The Research Foundation of the State University of New York (SUNY Buffalo) developed a fermentation process to produce anthocyanins and anthocyanidins. Researchers at the Rutgers University have reported a process in which soy protein isolates capture anthocyanins from dark-colored fruits juices. The products resulting from these technologies are, however, as yet unavailable in the open market and their commercial aspects, costs and generality of their technologies remain to be determined.
The purpose of this development is to report a simple, rapid and cost-effective and scalable method for isolation of pure anthos and other plant bioactives. The method reported here is based on the principle of solubility in specific solvents to isolate large quantities of anthos and other plant bioactives.